The lens focuses fast!!! and when it hunts - at all, it is dark to the point that I need to pack it up and head back to the house. It is also accurate.

What I meant when I wrote that focusing is critical, and I am finding this more and more with this lens (my really only fast lens), is that with the light, it (or I should say - I) slides into the f1.8, - 2.8 range too easily, and thus the DOF is very thin. I am finding that I need to stay up in the f4 area. I have been way too comfortable with my wider angle lenses with the accompanying deep DOF and they are comparatively slow (f4) when compared to the 31.

We were over at a friend's house yesterday for dinner and took some pictures. Again the thin DoF did me in. The items in focus were in sharp focus, with the rest in a pleasant slight blur. I opened up the ISO, and things got better. It is just a matter of learning to deal with a fast lens and the accompanying thin DOF, forcing the aperture up more, to open up the DOF. I am just not use to it - since my other slow lenses "automatically do it for me - already". The lazy photographer syndrome.

Interesting. I have a friend who bought an FA 31mm Limited to go with his K20 and he wound up sending it back - the first time I've ever heard of anyone doing this with this lens. He claimed it wasn't sharp enough or there were focusing problems. I think the honest truth is the narrow DOF was simply too much work for him.

Hi Brio, The lens is a lot of work, and it is sharp. That said, in order to use the fast aperture of the lens, you have to put up with the shallow thin DOF. I am working my way up thru the f stops. This evening I am going to go for the f4 and f5.6 to see how they turn out. Obviously, as I open up the aperture I get a deeper depth of field, which bring up the question, why such an expensive lens if all your going to do is us it at f4, 5.6 and 8. So, it is a some what unfair comparison against the 12-24, but I am thinking of also using the 16-45. I see all of this as increasing my skills and capabilities. I have the lens so why not use it.

John - I have not figured out exactly what to do with the sky. I think that its partially the lens as where the additional lights are are sufficient population centers on the other side of the hill, so there is additional light available in those particular areas. A lot of this is that the lens is so good that it highlights the imperfections of my skills. So we will see how all of this turns out. Also, part of it is that the lens vignettes at 1.8 and its trailing off at 2.8, so with the overall dark conditions, I think that what is there is amplified some. I am thinking of redoing it, but with some PP before stitching and then see how it looks...

Ah, now I understand what you've been finding. You are right that a fast lens like that is harder to use wide open - a very shallow DOF is difficult to deal with. But it does allow you to take pictures you might not have otherwise captured.

And it's still worth it, even if you use a smaller aperture - the bokeh of the 77 is incredible - at f5.6 it's still better than something like the 55-300. It has better contrast than even the DA*50-135. And it's the sharpest lens I own - I assume that your 31 is similar. All those things make it worth the extra cost and work. You might change the camera's program line to choose the sweet spot rather than normal. It'll probably choose to stop down the lens a bit - it chooses f4 for the DA*200 f2.8. Or else just keep an eye out for what aperture the camera is choosing and changing it if it looks too large.